Age-related Factors Which Influence the Value of the Mouse Embryo for Post-irradiation Restoration of the Adult

Summary

Strain XVII mice were given 800 r x-irradiation. In one group of experiments this was followed by injection of either 12- or 13-day isologous cells from the whole embryo. All mice that received cells from the 12-day embryos died at approximately the same time as irradiated controls. Among those receiving 13-day-embryo cells there was a 64 per cent 30-day survival-rate. In a second group, lethally-irradiated mice were given cells from either the liver and spleen or from the remainder of the carcass of 14-day foetuses, or, alternatively, from 18-day foetuses. The mice receiving liver and spleen cells from foetuses of either age enjoyed a good survival-rate. Of animals treated with carcass, there were numerous survivals only among those receiving 18-day carcass.

An attempt was made to explain the findings by histological investigation of both donors and recipients, and some possible explanations for the phenomena observed were advanced.